A semiconductor light-emitting diode (LED) includes a substrate, a light emitting region, a window structure, and a pair of electrodes for powering the diode. The substrate may be opaque or transparent. Light-emitting diodes which are based on gallium nitride (GaN) compounds generally include a transparent, insulating substrate, i.e., a sapphire substrate. With a transparent substrate, light may be utilized from either the substrate or from the opposite end of the LED which is termed the “window”.
The amount of light generated by an LED is dependent on the distribution of the energizing current across the face of the light emitting region. It is well known in semiconductor technology that the current flowing between the electrodes tends to concentrate in a favored path directly under the electrode. This current flow tends to activate corresponding favored portions of the light-emitting region to the exclusion of portions which fall outside the favored path. Further since such favored paths fall under the opaque electrode, the generated light reaching the electrode is lost. Prior art GaN LEDs have employed conductive current spreading layers formed of nickel/gold (Ni/Au), and have a gold (Au) window bond pad mounted on such layers. In such arrangements, the Ni/Au layer and/or the Au bond pad tend to peel during the wire bonding operation to the pad.